Difference between revisions of "Normal Parturition - Anatomy & Physiology"

From WikiVet English
Jump to navigation Jump to search
(58 intermediate revisions by 6 users not shown)
Line 1: Line 1:
−
{{OpenPagesTop}}
+
<big><center>[[Reproductive System|'''BACK TO REPRODUCTIVE SYSTEM''']]</center></big>
−
==Stages of Parturition==
+
 
 +
<big><center>[[Reproductive_System#Parturition|'''BACK TO PARTURITION''']]</center></big>
  
−
*Stage 1: this is the preparatory stage, starting at the onset of regular uterine contractions followed by cervical dilatation and the foetus assuming the correct disposition for passage through the birth canal.
 
−
*Stage 2: the expulsive stage, characterised by the onset of abdominal contractions which together with uterine contractions lead to foetal expulsion
 
−
*Stage 3: separation and expulsion of the foetal membranes. In polycotous species second and third stages are often inter-mixed.
 
  
−
The following table summarises the normal time taken to progress through the stages of parturition in different species.
 
 
{| style="width:75%; height:200px" border="1"
 
{| style="width:75%; height:200px" border="1"
  
Line 25: Line 22:
 
| '''Stage 2: Foetal Expulsion'''
 
| '''Stage 2: Foetal Expulsion'''
 
| 12-30 minutes
 
| 12-30 minutes
−
| 30 minutes - 4 hours
+
| 30-60 minutes
 
| 30-120 minutes
 
| 30-120 minutes
 
| 150-180 minutes
 
| 150-180 minutes
Line 41: Line 38:
  
  
−
The step in the reproductive process that immediately precedes lactation, uterine involution and return to cyclicity.  It is initiated by the foetus and involves a complex cascade of endocrine events. Parturition is the process by which the conceptus (foetus, placenta and placental membranes) is expelled from the [[Uterus - Anatomy & Physiology|uterus]]; this requires [[Cervical Softening - Anatomy & Physiology|cervical softening]],[[Uterine Contraction - Anatomy & Physiology|coordinated myometrial contractions]] and contraction of abdominal muscles
+
 
−
to occur
+
Parturition is the Process by which the conceptus (foetus, placenta and placental membranes) are expelled from the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|Uterus]] requires:
 +
* [[Parturition - Cervical Softening - Anatomy & Physiology|Cervical Softening]]
 +
* [[Parturition - Coordinated Myometrial Contraction - Anatomy & Physiology|Coordinated Myometrial Contraction]]
 +
* Voluntary contraction of abdominal muscles
 +
 
 +
 
 +
= Placental Expulsion =
 +
 
 +
In most species, expulsion of foetal membranes quickly follows expulsion of the foetus. 
 +
 
 +
* After the birth of the young, regular abdominal contractions largely cease.
 +
* Myometrial contractions persist.
 +
** Decreased amplitude, but become more frequent and less regular.
 +
** Important for dehiscence and expulsion of foetal membranes.
 +
* Waves of contractions from uterus to the cervix persist.
 +
** Act in a peristaltic fashion in the cow and sow in the reverse direction.
  
 
== Placental Changes ==
 
== Placental Changes ==
Line 58: Line 70:
 
* Open endometrial crypts
 
* Open endometrial crypts
 
* Foetal villi have shrunk due to the escape of blood from the foetal side of the placenta when the umbillical cord ruptures.
 
* Foetal villi have shrunk due to the escape of blood from the foetal side of the placenta when the umbillical cord ruptures.
−
* [[Uterine Contraction - Anatomy & Physiology|Myometrial contractions]] aid exsanguination of the placenta.
+
* Myometrial contractions aid exsanguination of the placenta.
 
* Separation of foetal membranes.
 
* Separation of foetal membranes.
 
* Apex of the allantochorionic sac becomes inverted.
 
* Apex of the allantochorionic sac becomes inverted.
Line 71: Line 83:
 
** Not the mare or camelids.
 
** Not the mare or camelids.
  
−
== Placental Expulsion ==
+
= Parturition Behaviour =
 +
 
 +
== Mare ==
 +
 
 +
=== Stage 1 ===
 +
 
 +
=== Stage 2 ===
  
−
In most species, expulsion of foetal membranes quickly follows expulsion of the foetus. 
+
=== Stage 3 ===
 +
 
 +
== Cow ==
 +
 
 +
=== Stage 1 ===
 +
 
 +
=== Stage 2 ===
  
−
* After the birth of the young, regular abdominal contractions largely cease.
+
=== Stage 3 ===
−
* Myometrial contractions persist.
 
−
** Decreased amplitude, but become more frequent and less regular.
 
−
** Important for dehiscence and expulsion of foetal membranes.
 
−
* Waves of contractions from uterus to the cervix persist.
 
−
** Act in a peristaltic fashion in the cow and sow in the reverse direction.
 
  
 +
== Ewe ==
  
−
== Parturition Behaviour ==
+
== Sow ==
  
−
=== [[Parturition Behaviour - Mare|Mare]] ===
+
=== Stage 1 ===
  
−
===[[Parturition Behaviour - Cow| Cow]] ===
+
=== Stage 2 ===
  
−
===[[Parturition Behaviour - Ewe| Ewe]] ===
+
=== Stage 3 ===
  
−
===[[Parturition Behaviour - Sow| Sow]] ===
+
== Bitch ==
  
−
===[[Parturition Behaviour - Bitch| Bitch]] ===
+
=== Stage 1 ===
  
−
===[[Parturition Behaviour - Cat| Cat]] ===
+
=== Stage 2 ===
  
 +
=== Stage 3 ===
  
−
{{OpenPages}}
+
== Cat ==
−
[[Category:Parturition]]
 
−
[[Category:Bullet Points]]
 

Revision as of 09:58, 4 August 2008

BACK TO REPRODUCTIVE SYSTEM
BACK TO PARTURITION


Species Mare Cow Ewe Sow Bitch
Stage 1: Contractions and Cervical Dilation 1-4 hours 2-6 hours 2-6 hours 2-12 hours 6-12 hours
Stage 2: Foetal Expulsion 12-30 minutes 30-60 minutes 30-120 minutes 150-180 minutes 6 hours (up to 24 hours with large litters)
Stage 3: Placental Expulsion 1 hour 6-12 hours 5-8 hours 1-4 hours Placenta Exits with Foetus



Parturition is the Process by which the conceptus (foetus, placenta and placental membranes) are expelled from the Uterus requires:


Placental Expulsion

In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.

  • After the birth of the young, regular abdominal contractions largely cease.
  • Myometrial contractions persist.
    • Decreased amplitude, but become more frequent and less regular.
    • Important for dehiscence and expulsion of foetal membranes.
  • Waves of contractions from uterus to the cervix persist.
    • Act in a peristaltic fashion in the cow and sow in the reverse direction.

Placental Changes

During the last 5 days of gestation, there are changes in the placenta.

  • Collaginisation of the placentome.
  • Flattening of maternal crypt epithelium.
  • Leucocyte migration and increased activity.
  • Reduction of binucleate cells in the trophectoderm.
  • Weakening of the acellular protein layer between cotyledonary and caruncular epithelium.

Contractions

  • Open endometrial crypts
  • Foetal villi have shrunk due to the escape of blood from the foetal side of the placenta when the umbillical cord ruptures.
  • Myometrial contractions aid exsanguination of the placenta.
  • Separation of foetal membranes.
  • Apex of the allantochorionic sac becomes inverted.
  • As the sac is 'rolled' down the uterine horns, foetal villi are drawn out of the crypts.
  • When a large portion becomes detached and inverted, it forms a mass in the maternal pelvis.
    • Stimulates reflex contractions of abdominal muscles.
    • Completes expulsion of the allantochorionic sac.
  • In polytocious species, dehisence and expulsion of foetal membranes are interspersed with births of the young.
    • Only expulsion of the last afterbirth stimulates abdominal contractions.
  • The final stage of allantochorionic expulsion lasts 1 hour (mare) - 6 hours (cow).
  • Domestic animals normally eat the afterbirth.
    • Not the mare or camelids.

Parturition Behaviour

Mare

Stage 1

Stage 2

Stage 3

Cow

Stage 1

Stage 2

Stage 3

Ewe

Sow

Stage 1

Stage 2

Stage 3

Bitch

Stage 1

Stage 2

Stage 3

Cat

Retrieved from "https://en.wikivet.net/index.php?title=Normal_Parturition_-_Anatomy_%26_Physiology&oldid=25556"